The invention relates to a method and to a device for pneumatic treatment of powder materials with a container connected to a feed line and a discharge for the material being conveyed.
EP 0 538 711 A reveals a conveying device, for example for plastic granules, with a hose line which, at one end, enters a storage silo by means of a lance and, at the other end, projects through a filter cartridge into a connecting branch which sits on the box-like inflow of a tangential feed opening of a plasticizing cylinder. A cover subassembly, through which the hose line likewise passes, is provided with a suction chamber via the filter cartridge. Said suction chamber has suction openings directed toward the connecting branch and is operatively connected to a nozzle system, to which compressed air or compressed gas can be supplied as the working medium. A relatively high negative pressure is generated in the suction chamber and propagates through the suction openings and the filter into the connecting branch and from there through the suction line into the storage silo. The working medium is intended to generate such a high pressure, by means of an increase in its speed, in the material being conveyed that the solid materials are sucked, by mixing with a suction air stream, to said box-like inflow. At the filters, the solid materials are separated from the suction air stream and the latter is mixed with the working medium. Cleaning of the filter can not be carried out during the process.
EP 0 574 596 A describes a system for the pneumatic transfer of cement from ships into silos by means of a “sluice-type container” comprising a plurality of container segments; an exhaust air filter sits in the uppermost container segment and the lowermost container segment tapers in the manner of a funnel.
Powder materials are also conveyed and transported in a controlled atmosphere in the chemical, pharmaceutical and foodstuffs industry. The known systems for conveying powder materials of this type are generally coordinated in terms of construction to the product to be subsequently conveyed; these systems are individual manufacturing systems causing high system costs.
The pouring of powder into reaction vessels or reactors within explosive zones takes place in general manually via a sluice or a protective valve, since most reactors do not have the necessary space for an adequate loading system. Such a manner of operation does not comply with the existing safety rules for preventing the risk of explosion; if the reactor is inerted, the manual pouring in of powders from the manhole leads to atmospheric pressures and neutralizes the protective effect of the inert gas. If solid materials are entered manually, the inerting is neutralized within a short time (O2 concentration>8%) and is not produced again even after relatively prolonged N2 flushing during operation.
In recognition of these circumstances, the inventor has set himself the aim of permitting cost-effective mixing and conditioning of powder materials.
The object is achieved by the present invention as described below.